Transcript for French Daredevils Attempt Heart-Stopping Hot Air Balloon Walk

Five days after we left the skyliners in France, we find ourselves in Spain. So, we're on the outskirts of Barcelona. Which way? Take a right. We should go left. To the left. Left. Turn right. Apparently, their holed up in an airplane liner preparing for the balloon stunt they've been dreaming of for years. It's for airplanes. No? When we finally arrive, tancrede greets us with some more news. I'm going to go to bed. We're leaving at 7:00 tomorrow morning. We won't sleep tonight we want to do it so bad. You're excited? Yes. Of course. Since they're on a shoe spring budget the teams must try to sleep in the airplane hangar where the balloons are kept. Get some rest or you will not enjoy the day. Good night. It's an ungodly hour. There's definitely an air of excitement. Anticipation is quite possible. I really do feel like we're on the verge of something. Let's hope it warms up a bit. Still sick and feverish, tancrede must reserve his energy for the day ahead. The team is attempting to take skylining to record breaking height, by crossing from one hot air balloon to another. We have to avoid these baskets. That's the first basket. No one seems to know if the stunt is even possible. You think he's going to -- At least, it's nice to try it. So you're not very popular. I don't know. I -- unless I'm feeling sick, or -- I'm kind of not understanding what's happening. It's really weird vibe. It's almost like they've crossed over to the dark side. Maybe this is them psychologically preparing themselves for this crazy walk. This is the only people without a parachute. Are you making this up? No. I did not hear that. Funny they kept that from us. Are you joking? No, seriously. Sounds like this is a cruel joke, but my panic sets in. When we arrive at the launch site, I see them preparing carefully. I don't know if this is going to work or not. These are also engineers by training. They test every element of the stunt before takeoff. To see all of the technical aspects and be able to do it, that's very interesting. This is crazy, huh? I'm starting to get excited. You're excited? Yeah. It's time for me to decide. I consider all of the risks and I realize, I trust them. Suddenly I know I'm able to go up in that balloon. I never dreamt of going in a hot air balloon, but I'm really excited. The three balloons all tethered together, we start climbing. Tell us just how tight we are here. No. Stop asking me these questions, because then it's going to make me start thinking about where we are, suspended, hundreds of feet in the air and climbing. Who's going first? It seems like I'm going first. You're the Guinea pig. Yeah, I'm the Guinea pig. I know. Freddie? Yeah. Are you nervous? Yeah. They're trying to rig up the line. I'm focusing on staying alive. He's going up. He's going up on the slack line. I cannot believe it. Look at him, he's about to go. You came to this point knowing that everything was prepared. You have enough experience. You always, always kind of a risk. This is why you have this feeling. Actually, it's good. It helps to keep you alive. Oh, my god. Holding on to the basket, at least I feel like I have some control. It's very, very hard. I hope Julien is going to make it, to give me some power to cross. Yes. Whoa! My god. Will your parachute open? Tancrede steps up one more time. Time. Oh, my god, oh, my god. Pull the plug dark pull the plug -- pull your parachute. Whoo hoo! Sadly, they're dropping like flies. Oh, but I think all of them are pulling it way too late. The pilot just told us the best news, we're going to land. Best news I've heard all day. Now the guys are telling us, you got to push yourself and you have to face your fear. I have pushed myself, like I've never pushed myself rebefo. But for the record, imactually never going up in a balloon again. Oh, my god. Tancrede! The flying frenchies, on the other hand, they're just getting started. It was good. This is the journey. We're leaving the first flight. The first fall, the first question. And now we aim for the achievement. It's not yet here but it's not

This transcript has been automatically generated and may not be 100% accurate.

'Flying Frenchies' Tempt Fate With Wild Sky-High Stunts

Part 1: French group lives for the thrill of pushing their instincts to the limit and cheating death.